Nelson Mandela is celebrating his 85th birthday on Friday and tributes are pouring in from around the world.

A special website has been set up and messages collected are to be presented to Mr Mandela on CD-Roms.

The South African phone company Telkom and national broadcaster SABC are also trying to break the world record for phone tributes and raise money for Mr Mandela's children's charity.

While world leaders sent formal messages of congratulations, ordinary people had already sent more than 34,000 text messages (SMS) and 20,000 telephone message greetings by Friday evening, BBC News Online was told.

South African President Thabo Mbeki was among the first to pay tribute to his predecessor.

"All of us as a country are indeed very blessed, that we have somebody like him, who has led the life that he has and helped to create the kind of South Africa that we now have," Mr Mbeki said.

Throughout Friday, numerous renditions of "Happy Birthday" were sung at his Johannesburg home as a 35-member band played a specially-composed "Madiba March" and "Happy Birthday" on brass instruments and bagpipes.

Cake

Mr Mandela and his wife Graca Machel later cut a birthday cake and distributed pieces to disabled children.

There was a flypast of one of South African Airways' new planes which is to be named the "Nelson Mandela".

Mr Mandela is spending the rest of Friday with family including more than 30 grand- and great-grand-children, who were hosting a dinner party for him.

There were also congratulations from former US president Bill Clinton and retired Anglican archbishop of Cape Town Desmond Tutu among many.

'New depth'

Tutu said the years his friend spent in jail "gave him a new depth, helped him to be more understanding of the foibles of others, to be more generous, more tolerant, more magnanimous and it gave him an unassailable credibility and integrity."

The celebrations are to culminate with a high-profile banquet in Johannesburg on Saturday, with guests including Clinton, US talk show host Oprah Winfrey and Bono of the Irish rock band U2, as well as his cook and gardener.

On Thursday, he was presented with a book of tributes from world leaders.

The internet tribute page at the South African web site www.safrica.info will remain open until the end of July.

"We're encouraging people around the world to phone their tributes to Mandela," Telkom spokesman Andrew Weldrick told BBC News Online.

"Any profits made will be paid to the Nelson Mandela Children's Fund," he said.

The organisers are also hoping to receive several million phone calls and text messages.

These will all be recorded but Mr Weldrick says it is unlikely that Mr Mandela will have time to listen or read them all.